1. FIELD OF THE INVENTION
The present invention is directed to a pulley assembly intended for improving the operative relationship between a winch and a cable or rope actuated thereby.
2. DESCRIPTION OF THE PRIOR ART
Hoisting apparatus, notably those intended for flying scaffolds and the like, wherein there are provided two or more pulleys around which the load-supporting cable or rope is or are caused to pass, are already known. These apparatus are so designed that the cable moves on the pulleys of the assembly without being wound on a drum, or at least, in the case of powered apparatus, on the drum driven by the hoisting motor.
Some of these known arrangements comprise a grooved pulley having a V-shaped groove or an equivalent cross-sectional contour in order to wedge or jam the cable so that the latter, due to the stress exerted by the load, is eventually more or less damaged.
Other known systems comprise only pulleys the grooves of which have a semi-circular cross-sectional contour which does not appreciably damage the cable but reduces the cable adherence, thus entailing considerably stronger cable pressing means constituting a cause of excessive stress of the component elements.